Hydrocarbon adsorbent state determining apparatus

Abstract

A hydrocarbon adsorbent state determining apparatus is provided for compensating the ability of a hydrocarbon adsorbent to adsorb moisture for fluctuations due to a change in the flow velocity of exhaust gases to accurately determine the state of the hydrocarbon adsorbent, including a deterioration thereof, irrespective of the change in the flow rate of exhaust gases. The hydrocarbon adsorbent state determining apparatus determines the state of a hydrocarbon adsorbent disposed in an exhaust system of an internal combustion engine for adsorbing hydrocarbons and moisture within exhaust gases. The hydrocarbon adsorbent state determining apparatus comprises a downstream humidity sensor for detecting the humidity of exhaust gases which have passed through the hydrocarbon adsorbent, a flow velocity parameter detector for detecting a flow velocity parameter indicative of a flow velocity of the exhaust gases, and an ECU for determining the state of the hydrocarbon adsorbent in accordance with the detected humidity of the exhaust gases and the flow velocity parameter.

1. A hydrocarbon adsorbent state determining apparatus for determining a state of a hydrocarbon adsorbent disposed in an exhaust system of an internal combustion engine for adsorbing hydrocarbons and moisture within exhaust gases, said apparatus comprising:
 humidity detecting means for detecting the humidity of exhaust gases which have passed said hydrocarbon adsorbent;  
 flow velocity parameter detecting means for detecting a flow velocity parameter indicative of a flow velocity of the exhaust gases; and  
 adsorbent state determining means for determining the state of said hydrocarbon adsorbent in accordance with the detected humidity of the exhaust gases and the flow velocity parameter.  
 
   
   
     2. A hydrocarbon adsorbent state determining apparatus according to  claim 1 , wherein said adsorbent state determining means determines the state of said hydrocarbon adsorbent in accordance with a change in a detected value of said humidity detecting means from a start of said internal combustion engine. 
   
   
     3. A hydrocarbon adsorbent state determining apparatus according to  claim 2 , further comprising:
 a temperature state detecting means for detecting a temperature state of said hydrocarbon adsorbent,  
 wherein said adsorbent state determining means determines the state of said hydrocarbon adsorbent in accordance further with the temperature state of said hydrocarbon adsorbent upon start of said internal combustion engine detected by said temperature state detecting means.  
 
   
   
     4. A hydrocarbon adsorbent state determining apparatus according to  claim 1 , further comprising:
 upstream humidity detecting means disposed at a location upstream of said hydrocarbon adsorbent in said exhaust system for detecting the humidity of exhaust gases which flow into said hydrocarbon adsorbent,  
 wherein said adsorbent state determining means determines the state of said hydrocarbon adsorbent in accordance further with the humidity detected by said upstream humidity detecting means.